The key Brexit dates in 2018 and 2019 – from the EU summit to the 'meaningful vote' and the end of the transition period

25 November – Brussels signed off May's EU withdrawal deal

In one of the most concrete outcomes to so far manifest itself, Brussels agreed to UK's Brexit deal at a Brussels summit.

After 20 months of negotiations, the 27 EU leaders gave the deal their blessing after less than an hour's discussion.

May vowed to make a case for the deal "with all my heart".

The PM said the deal "delivered for the British people" and set the UK "on course for a prosperous future".

11 December – 'Meaningful vote' cancelled

Parliament was due to hold a 'Meaningful Vote' on the Brexit deal. Britain can only leave the EU if MPs and EU leaders agree on the same deal.

After promising she wouldn't, the PM cancelled the vote at the eleventh hour in the face of near-certain defeat.

12 December – May narrowly survives vote of no confidence

A vote of no confidence in Theresa May's leadership was triggered after the critical number of 48 Tory MPs wrote in to the Chairman of the 1922 Committee.

The PM secured the support of 200 Tory MPs, enough to stay in post, but worryingly 117 called for her to go.

The result of the vote means May cannot be challenged by her own MPs again before the end of her five-year term, 2022.

13-14 December – May fails to sweeten the deal

May attended a planned EU summit – but failed to get any notable concessions to her deal.

Instead the 27 Europe leaders told her to return to Parliament to make her MPs back the agreement.

7 January – MPs returned from Christmas recess

15 January – 21 January – 'meaningful vote' crunch time?

A 'meaningful mote' on May's EU withdrawal deal has been rescheduled for next Tuesday,January 15.

May is allowed to force further votes on her deal in the hope that MPs will finally give in.

But under parliamentary convention the motion would have to be amended in some form before a second vote.

Rival groups of MPs could put forward their proposals – such as a second referendum and a Norway-style membership.

Commons speaker John Bercow will have a key role in managing the fraught process.

If May loses the meaningful vote, she has only three days to come back to Commons with a plan B.

In any case, May only has until Monday, January 21 to provide a fallback plan.

If the government has not presented its withdrawal agreement by this date, powers for MPs to influence ministers' next steps will kick in.

If they fail to agree on a deal, Britain will be headed for a no deal Brexit.

21-22 March – UK's final summit as EU member

Until 29 March – EU ratification

When or if the UK does finally agree on a deal, the European Parliament will then have to approve this in a plenary vote.

EU member states will also have to give the deal final approval in a ministerial meeting.

29 March – Brexit Day

It's currently agreed that the UK has to leave the EU by 11pm on Friday, 29 March. A special summit of the 27 other EU countries soon after the UK's exit is expected, but has not yet been scheduled.

It's possible though that Parliament might request an extension to the Article 50 process – for example if they needed more time to approve the withdrawal bill (which is beginning to look very likely.)

A final alternative would be for the UK to revoke Article 50 and decide to remain in the EU for good. The European Court of Justice ruled in December 2018 that Britain could still do this.

However, Downing Street has stated this will not happen. The official position of both Labour and Conservatives is to go through with the 2016 Brexit referendum result.

31 December – An end to EU membership?

If Britain was to start the withdrawal process on March 29, 2019, the end of 2020 would mark an official end to the UK's EU membership.

However, given the ongoing certainty surrounding Brexit no date is really a given.

The EU treaty says that the transition COULD be extended up to December 31, 2022 – but Downing Street has so far said it's determined not to extend it.